Single or Dual plane intake manifold?
10-13-2003 | 10:02 AM
#31
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Joined: Mar 2001
Posts: 1,620
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From: st. clair shores mi ,us
I guess my .680" 256/[email protected] solid roller was too big for my 8.5:1cr 502 ?
You mean I coulda made more than 625hp ?!?
I know every boat and motor combo is different. In my application I could care less about lowend. It's a bravo boat and would be babied on plane all the time anyways. I was interested in top end and mid range. I also didn't care if I spun the motor 5800 either.
You mean I coulda made more than 625hp ?!?
I know every boat and motor combo is different. In my application I could care less about lowend. It's a bravo boat and would be babied on plane all the time anyways. I was interested in top end and mid range. I also didn't care if I spun the motor 5800 either.
10-13-2003 | 11:30 AM
#33
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Joined: Mar 2001
Posts: 1,620
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From: st. clair shores mi ,us
Roby,
It idles in gear at 700rpms with at 1050 Dominator. It is also now a 540.
Even if I knew how to do the sound file thing I couldn't, the boat is winterized and sitting in a barn about 2.5hours from my house. There are some people on this board that have seen and heard it and will vouch.
It idles in gear at 700rpms with at 1050 Dominator. It is also now a 540.
Even if I knew how to do the sound file thing I couldn't, the boat is winterized and sitting in a barn about 2.5hours from my house. There are some people on this board that have seen and heard it and will vouch.
10-13-2003 | 06:17 PM
#34
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Joined: Dec 2000
Posts: 1,340
Likes: 28
From: Harwich, MA
Dennis,
If what robyw1 is saying is the case, I should of gained power by going to a dual plane over the Dart, but the opposite is what happened when I tried it??
The boat idles a little rough, but certainly managable.
I'm turning 5300rpm now with a labbed 25"Mirage plus. Are you telling me I could turn 5400 or 5500rpm with a little less cam??
I installed this cam on the advice of a well respected engine builder, the same builder that did the machine work on the block and heads. This cam was a custom grind that he has come up with after trying a number of grinds in similar motors. This cam replaced a Comp 226/234 @.050 with .598/.610 lift , I gained 100 rpm over it!
It's not a big deal to swap it out again, so if you can give me some specifics that you are sure will give me more power I'm all ears!!
If what robyw1 is saying is the case, I should of gained power by going to a dual plane over the Dart, but the opposite is what happened when I tried it??
The boat idles a little rough, but certainly managable.
I'm turning 5300rpm now with a labbed 25"Mirage plus. Are you telling me I could turn 5400 or 5500rpm with a little less cam??
I installed this cam on the advice of a well respected engine builder, the same builder that did the machine work on the block and heads. This cam was a custom grind that he has come up with after trying a number of grinds in similar motors. This cam replaced a Comp 226/234 @.050 with .598/.610 lift , I gained 100 rpm over it!
It's not a big deal to swap it out again, so if you can give me some specifics that you are sure will give me more power I'm all ears!!
08-27-2023 | 08:06 AM
#35
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Joined: Oct 2000
Posts: 4,541
Likes: 107
From: Western Michigan
Dennis,
If what robyw1 is saying is the case, I should of gained power by going to a dual plane over the Dart, but the opposite is what happened when I tried it??
The boat idles a little rough, but certainly managable.
I'm turning 5300rpm now with a labbed 25"Mirage plus. Are you telling me I could turn 5400 or 5500rpm with a little less cam??
I installed this cam on the advice of a well respected engine builder, the same builder that did the machine work on the block and heads. This cam was a custom grind that he has come up with after trying a number of grinds in similar motors. This cam replaced a Comp 226/234 @.050 with .598/.610 lift , I gained 100 rpm over it!
It's not a big deal to swap it out again, so if you can give me some specifics that you are sure will give me more power I'm all ears!!
If what robyw1 is saying is the case, I should of gained power by going to a dual plane over the Dart, but the opposite is what happened when I tried it??
The boat idles a little rough, but certainly managable.
I'm turning 5300rpm now with a labbed 25"Mirage plus. Are you telling me I could turn 5400 or 5500rpm with a little less cam??
I installed this cam on the advice of a well respected engine builder, the same builder that did the machine work on the block and heads. This cam was a custom grind that he has come up with after trying a number of grinds in similar motors. This cam replaced a Comp 226/234 @.050 with .598/.610 lift , I gained 100 rpm over it!
It's not a big deal to swap it out again, so if you can give me some specifics that you are sure will give me more power I'm all ears!!
08-27-2023 | 03:51 PM
#37
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Joined: Feb 2001
Posts: 4,303
Likes: 1,459
From: Virginia Beach
Old thread but considering I have a pair of his carburetors, I’ll chime in.
I have single planes (Merlin) on the 509s in my 311. This thing is no where near lacking on torque and gets and gets right up on plane. Leading up to peak torque (about 47-4800) the power is really strong. Just trying to get the tune right on the top end at this point.
My understanding is that the dual plane on a marine setup with really good flowing modern heads (in my case AFR 320s) can actually hinder performance. And with that, dual plane intakes were never a consideration with what I built.
No clue on the sailboat thing… but I know he was working on another boat with supercharged motors (he didn’t like the Demon’s and that’s how I got them… duh.. one of the carbs had the main well completely open to atmosphere! - poor quality control I guess).
I have single planes (Merlin) on the 509s in my 311. This thing is no where near lacking on torque and gets and gets right up on plane. Leading up to peak torque (about 47-4800) the power is really strong. Just trying to get the tune right on the top end at this point.
My understanding is that the dual plane on a marine setup with really good flowing modern heads (in my case AFR 320s) can actually hinder performance. And with that, dual plane intakes were never a consideration with what I built.
No clue on the sailboat thing… but I know he was working on another boat with supercharged motors (he didn’t like the Demon’s and that’s how I got them… duh.. one of the carbs had the main well completely open to atmosphere! - poor quality control I guess).
08-27-2023 | 08:19 PM
#39
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Joined: Jan 2003
Posts: 6,023
Likes: 1,522
From: Grand Rapids, MI
I have single planes (Merlin) on the 509s in my 311. This thing is no where near lacking on torque and gets and gets right up on plane. Leading up to peak torque (about 47-4800) the power is really strong. Just trying to get the tune right on the top end at this point.
My understanding is that the dual plane on a marine setup with really good flowing modern heads (in my case AFR 320s) can actually hinder performance. And with that, dual plane intakes were never a consideration with what I built.
My understanding is that the dual plane on a marine setup with really good flowing modern heads (in my case AFR 320s) can actually hinder performance. And with that, dual plane intakes were never a consideration with what I built.
Glad to hear your 509's are performing!
08-27-2023 | 10:30 PM
#40
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Joined: Oct 2000
Posts: 4,541
Likes: 107
From: Western Michigan
Old thread but considering I have a pair of his carburetors, I’ll chime in.
I have single planes (Merlin) on the 509s in my 311. This thing is no where near lacking on torque and gets and gets right up on plane. Leading up to peak torque (about 47-4800) the power is really strong. Just trying to get the tune right on the top end at this point.
My understanding is that the dual plane on a marine setup with really good flowing modern heads (in my case AFR 320s) can actually hinder performance. And with that, dual plane intakes were never a consideration with what I built.
I have single planes (Merlin) on the 509s in my 311. This thing is no where near lacking on torque and gets and gets right up on plane. Leading up to peak torque (about 47-4800) the power is really strong. Just trying to get the tune right on the top end at this point.
My understanding is that the dual plane on a marine setup with really good flowing modern heads (in my case AFR 320s) can actually hinder performance. And with that, dual plane intakes were never a consideration with what I built.
Thanks for your input.
Last edited by KAAMA; 08-27-2023 at 10:33 PM.
